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Permanent link (DOI): https://doi.org/10.7939/R3M628

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Iceberg calving from a Canadian Arctic tidewater glacier Open Access

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Other title
Subject/Keyword
Canadian Arctic
Belcher Glacier
iceberg calving
tidewater glacier
time lapse image
Type of item
Thesis
Degree grantor
University of Alberta
Author or creator
Milne, Hannah Maree
Supervisor and department
Sharp, Martin (Earth and Atmospheric Sciences)
Examining committee member and department
Hicks, Faye (Civil and Environmental Engineering)
Croitoru, Arie (Earth and Atmospheric Sciences)
Department
Department of Earth and Atmospheric Sciences
Specialization

Date accepted
2011-08-31T17:57:38Z
Graduation date
2011-11
Degree
Master of Science
Degree level
Master's
Abstract
Time lapse imagery, an audio recorder and geophones were used to detect iceberg calving events on the Belcher Glacier, Devon Island, in the Canadian High Arctic, in order to identify the major controls on the rate and style of calving. Eleven calving events were identified between June 4th and August 14th 2009 which accounted for 44% of the annual calving flux. Several of the events recorded in the audio data were associated with debris avalanching and disintegration of large tabular bergs. The geophones did not identify calving events but did record hydro-fracturing when terminus water-filled crevasses drained into the glacier. None of the calving events were a direct response to an increase in ice velocity in the terminus region, break-up of the sea ice/mélange, tidal flexure of the terminus, or propagation of water-filled crevasses. The Belcher Glacier maintains a lightly grounded stable terminus position but develops a protrusion at the glacier centreline every few years. When this occurs, as it did in 2009, the meltwater plume is active in eroding the lateral stability of the protrusion by locally enhancing the calving rate. Further investigation is required to examine whether basal melt also undercuts the protrusion, eventually leading to its flotation. In 2009 the protrusion calved off as a series of tabular icebergs which strongly suggests it was floating, as do calculations of height-above-buoyancy and subglacial effective pressure. In general, calving was not driven by a single identifiable cause and its stochastic timing may reflect the progressive accumulation of damage to the ice as it is transported to the terminus. The interactions of ice flow with the ice and bed geometry, as well as ponding and hydro-fracturing of supraglacial meltwater, seemed to be the main contributors to this damage.
Language
English
DOI
doi:10.7939/R3M628
Rights
License granted by Hannah Milne (hmmilne@ualberta.ca) on 2011-08-30T19:32:18Z (GMT): Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of the above terms. The author reserves all other publication and other rights in association with the copyright in the thesis, and except as herein provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.
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File title: MSc Thesis
File author: Hannah Milne
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